In this type of disk device, it is required that the rotation center of a disk rotation driving unit (for example, spindle motor) for rotating a turntable on which a disk is mounted be positioned with high precision to the position of a lens of an optical pickup.
Conventionally, for the purpose of the positioning, the positions of a guide shaft for moving an optical pickup in a radial direction of a disk and the rotation center of a disk rotation driving unit are generally adjusted to fall within a prescribed dimensional tolerance. This is a restriction to ensure the reproduction ability of the optical pickup, and the dimensional tolerance is prescribed in a specification or the like of the optical pickup; the positioning is performed by moving the disk rotation driving unit to the guide shaft or by moving the guide shaft to the disk rotation driving unit. A public known example of moving a guide shaft is found in Patent Document 1.